Air operated switch



Patented June 18, 1940 UNITED STATES PATENT OFFICE AIR OPERATED SWITCHApplication November 19, 1937, Serial No. 17 5,425

9 Claims.

This invention relates to electric switches of the quick make and breaktype, and particularly to those actuated by air streams of varyingintensity.

One object of the invention is to provide a switch sensitive enough torespond to air streams of low potential, and that will effect a quickmake and a quick break of the circuit connections with a minimum ofarcing at the contact points.

A further object is to provide a sensitive circuit control mechanism,with means for critically adjusting the point of contact opening andcontact closing.

A further object of the invention is to provide means in a sensitiveswitch for holding the contacts in a normally closed position untilpredetermined conditions are experienced, and on the manifestation ofwhich the contacts will open with a snap action.

A further object of the invention is to provide means for criticallyadjusting the mechanism to a desired point of contact opening, as wellas to a desired point of contact closing,

a which two points of contact actuation may be relatively widelyseparated.

A further object of the invention is to provide an air operated switch,in which the contacts will be maintained closed for predetermined lowpotential air streams, and will thereupon open with a snap action andremain open even though the air stream potential may fall to a lowervalue than that of the initial actuating force, whereupon the contactswill close through the influence of the same means with a snap action.

A further object of the invention is to provide magnetic holding meansin a switch device, whereby the contact opening and the contact closingwill both be responsive to the snap action.

A further object of the invention is to provide a magnetic holding meansfor circuit closers, wherein the holding function can be adjusted tosuit the conditions under which the switch is used.

A still further object is to provide an electric switch of the normallyclosed contact type, that will work with a snap action to open a circuitin response to a predetermined actuating force, and thence operate toclose a circuit in response to a predetermined actuating forcematerially less than the force required to open the circuit.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing wherein a preferred embodiment of the present invention isclearly shown.

In the drawing:

Fig. 1 is a plan view with parts shown in section, illustrating one formof an air stream sensitive switch, the parts being illustrated in thecircuit closed position.

Fig. 2 is a similar view, illustrating the parts moved to a circuit openposition.

Fig, 3 is a transverse sectional view, substanw tially as indicated bythe line and arrows 3-3 of Fig. 1.

Fig. 4 is a transverse sectional view, substantially as indicated by theline and arrows 4-4 of Fig. 1.

Fig. 5 is a top plan view, of a modified form of an air streamresponsive switch, the contacts being shown in the circuit closedposition.

Fig. 6 is a similar view, showing the parts moved to circuit openposition.

Fig. 7 is a side elevation, of the form shown in Fig. 5.

Fig. 8 is a transverse sectional view, substantially as indicated by theline and arrows 8-8 of Fig. 5, and Fig. 7.

In the art of air operated switches, much difficulty has beenexperienced in designing and calibrating a mechanism that would besensitive enough to respond to slight variations in air velocities oflow magnitude, and yet would be rugged enough to give extended service,and not be damaged by continued and hard usage. Other difficulties havepresented themselves in the way of causing a flutter of the actuatingelement, when subjected to air streams but little difierent in forcethan that at which the device Was set to respond. As an example, supposeit be desirable to have an air operated switch preform a circuit openingfunction at 15 m. p. h., and that the switch isinstalled upon a vehicleoperating at a speed of perhaps 15.5 m. p. h. Under this assumption, theair force upon the vane of the switch, for some reason or other might begusty in nature, but in any event Would result in an irregular thoughfrequent and alternate contact opening and contact closing functionwithout any apparent change of vehicle speed. The result is undesirable,since the control effected by the switch would thereby be irregular anduncertain, if not undesirable.

The foregoing objects have been accomplished, and the stated problemshave been solved, by incorporating a holding means that is adapted tostandardize, or stabilize, the contact actuation at the low air streamvelocities, in that the con- June 18, 1940. E. M. CLAY TOR AIR OPERATEDSWITCH Filed Nov. 19, 19:7

n 5 4 I 7 7 7 I 5 F Z y ws m n 9 TU N J m m L WM n F i 5 Y O 4MB 0 arml9, by means of an air vane or paddle. 2|. Return movement of the arm l9to the rest position is assured by a spring 23, one end 25 of which ishooked upon one or another of a plurality of lugs 21, on the arm l9,while the other end 29 hooks behind one or another of a plurality oflugs 3| of a plate 33, secured to the plate II by the end of the sleevel5, which is peened over or otherwise secured asat 35. The arm l9 has anextension 3! that ends in an armature portion 39 urged into closeproximity to a magnet 4| supported by a block of insulation 43, whichinsulated block is in turn secured to the base II by means of ashouldered stud 45. The extension 31 supports a movable contact 41, andthe intermediate portion is looped or bowed as: at 49 to partiallyembrace the stud 45, when the contact bearing arm ismoved into thecircuit open position, substantially as illustrated in Fig. 6.Surrounding the magnet 4|, or at least disposed between the magnet 4|and the armature portion 39, there is a piece of nonmagnetic material 5|that prevents freezing of the armature 39 to the magnet 4| when theswitch device is in the rest position.

A relatively fixed contact 53 is mounted on a spring arm 55, extendingfrom a bracket 51 mounted in insulated relation on the base I, and isprovided with an exterior terminal 59.

Means are provided for securing a cover assembly over the working parts,as in the form earlier described, though no cover is shown in thedrawing, and contemplates passing the cover aperture over the threadedprojecting end of the stud 45, where it may be secured by a nut on theexterior thereof as in the earlier described form. For the purpose ofpositioning or locating the flanged edge of the cover, the base H isfashioned to provide the squirts or extrusions 6| in the base II, thatengage with the inner surface of the cover flange. In the formillustrated in Figs. 1 to 4, these extrusions are likewise shown in theposition relative to the cover 96. In either instance an appropriategasket 63, for perfecting a weather tight seal, may be inserted betweenthe edge of the cover and the base.

Either modification of the switch structure provides a device that issensitive, or can be adjusted to be sensitive, to air stream movementsof low potential, though the structure in either instance is rigidenough to properly function throughout a long period of service. Afteronce being adjusted it needs no further attention to operate withunfailing fidelity under the desired conditions.

As for operation, in controlling the circuits within which they areinserted, either device is equally effective. Let it be assumed that theswitch is to be inserted in a circuit, such as the volume control ofradio, or a lock-out for free wheeling, and particularly the latterwherein it may be desirable to disconnect the free wheeling feature fromthe automobile for engine speeds above 20 m. p. h., and maintain thatcircuit open until the car speed falls below m. p. h. The physicalstructures are thence adjusted such that the air stream indicated atI00, created by the engine cooling fan or other air moving device willactuate the paddle 24 with sufficient force to overcome the holdingforce of the return spring and the magnet or the holding device. Underthese conditions as soon as the armature of the contact carrying armstarts to move away from the magnet, the magnetic force by which thecontacts have been maintained in circuit closed position, rapidly fallsaway, and the stored up pressure against the paddle 24, having anappreciable portion of its resisting force done away with, is effectiveto snap the armature against the stops, it being attended by a quickbreak of the circuit connections. On the other hand, should theimpelling force against the paddle 24 or 2| fall away even to a lowervalue than that at which the contacts are open, the circuit connectionswill be maintained open, until the force acting upon the paddle 24approaches the value at which the mechanism has been adjusted to cut-in,or reestablish. This cut-in value may in the assumed instance be at avehicle speed of about 15 m. p. h. or some other speed less than theassumed m. p. h. for circuit opening. This is made possible by reason ofthe fact, that as the wind pressure upon the paddle 24 decreases, thereturn spring will tend to retract the armature toward its restposition, and during which it approaches and finally becomes re-immersedin the field of the magnet. When this approach is sufficient that thearmature is disposed in attractive relation with respect to the magnet,then the return force of the contact supporting arm is accelerated,which manifests in closing of the contacts with a snap action.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is a follows:

1. An air operated switch comprising in combination, an oscillatableshaft, an arm driven by the shaft and carrying a movable contact, meansproviding a relatively fixed contact in cooperable relation therewith,said shaft and arm being spring urged to contact closed position, magnetmeans for pulling upon the arm when the contacts are in closed relation,and an extension of said arm adapted to be attracted by the magnet meanswhen the contacts are in wide open rela-- tion.

2. An air operated switch comprising in combination, a vane responsiveto movement of air currents, a contact carrying arm having a flange withan offset, a shaft rigidly joining the vane and arm, a base supportingthe shaft for oscillatable rotation, a permanent magnet rigidly fixed tothe base, spring means urging the flange of the arm into the field ofthe magnet, said vane being operable to move the arm flange out of themagnetic field, and to move the flange off-set into the field.

3. The combination set forth in claim 2, wherein stops are provided forlimiting the approach of the arm and offset toward the magnet.

4. An air operated switch comprising in combination, a vane responsiveto movement of air currents, a contact carrying arm having a flange withan offset, a shaft rigidly joining the vane and arm, a base supportingthe shaft for oscillatable rotation, a permanent magnet rigidly fixed tothe base, spring means urging the flanges of the arm into the field ofthe magnet, said vane being operable to move the arm flange out of themagnetic field, and to move the flange off-set into the field and meansincluding spring supporting lugs provided by the arm for altering theurging frame by which the arm is moved into the field of the magnet.

5. An air operated snap switch, comprising in combination, a baseproviding a relatively fixed contact, an oscillatable arm carrying amovable contact, an armature having an angular offset carried by thearm, means normally urging the arm into contact closed position, magnetmeans mounted on the base and whose field normally immerses the armaturewhile the contacts are closed, an air operated vane for moving the armto contact Open position, and for withdrawing the armature from themagnetic field and means for preventing engagement between the armatureand magnet means.

6. The combination set forth in claim 5, wherein the last named meanscomprises an adjustable stop engaging the arm in its rest position.

7. The combination set forth in claim 5, wherein the last named meanscomprises a non magnetic member disposed between the arm and the magnet.

8. An air operated switch having open-contact and closed contactpositions and comprising in combination, an oscillatable shaft, an armdriven by the shaft and carrying a movable contact, means for providinga relatively fixed contact in cooper-able relation therewith, said shaftand arm being spring urged to one contact relation, magnet means forpulling upon the arm while in the said last mentioned contact relation,and an extension of said arm adapted to be attracted by the magnet meanswhile the arm is in the other contact relation, and actuating meansincluding an air operated vane for moving the arm from the spring urgedcontact relation to said other contact relation.

9. A switch having relatively movable contacts and operable into circuitopen and circuit closed positions, a shaft, an arm driven by the shaftfor moving one of the contacts, a vane for moving the shaft to operatethe switch into one position, a spring for moving the shaft to operatethe switch into another position, magnet means pulling on the arm whenin one switch position, and an extension of said arm attracted by themagnet when the switch is in another position.

EDWARD M. CLAYTOR.

